The question has gone viral since one of his students posted it to Twitter.

What kind of professor, indeed? University of Maryland psychology teacher Dylan Selterman has been adding it to his test since 2008. The question reads:

Select whether you want 2 points or 6 points added onto your final paper grade. If more than 10% of the class selects 6 points, then no one gets any points. Your responses will be anonymous to the rest of the class, only I will see the responses.

The question illustrates a theory called "The Tragedy of the Commons," which means a situation where individuals act according to their self-interest, and against the interests of the whole group, eventually depleting some common resource. Like quiz points, for example. Since he started adding it to his tests, only one class has managed to get the extra credit, 2 points apiece.

Sources: Shahanye | h/t BuzzFeed